Billie Joe Armstrong and Billie Eilish. Green Day got things started at the Kia Forum, where they surprised fans with Eilish to help them perform, "Last Night on Earth" from 2009's 21st Century Breakdown.

Billie Eilish made a surprise appearance on stage with Green Day on Thursday to kick off one of two star-studded concerts in Los Angeles put together to raise funds for people affected by deadly wildfires in California this month.

Green Day opened the show with their song “Last Night on Earth,” featuring a surprise appearance by Billie Eilish, and then followed up with their anthem “Still Breathing”

Billie Eilish and Finneas, Olivia Rodrigo, Earth, Wind & Fire, Gracie Abrams, Green Day, Jelly Roll, Joni Mitchell, Katy Perry, Lady Gaga, Lil Baby, Pink, Red Hot Chili Peppers, Rod Stewart, Sting, Stevie Nicks and Tate McRae are among those performing at the dueling shows at L.

One of the great challenges faced by the events during Grammy Week, including the FireAid benefit, is how to set the proper tone: How do you have a celebratory event like big concert or awards show without seeming tone-deaf to the tragedy and loss so many suffered in the Los Angeles wildfires that ravaged the

Billie Eilish made an appearance during Green Day’s set at the FireAid concert on Jan. 30. The Grammy winner came out as the rock band was performing “Last Night on Earth” and sang a stunning rendition of the song with them.